Endoscopes are used to view internal tissue of humans, and for many other tasks. Endoscopes are used to acquire high quality images, and allow access to body tissue for taking biopsy samples, delivery of therapeutic means and/or introduction of fluids. It is desired to allow easy maintenance and sterilization of endoscopes.
U.S. Pat. No. 4,895,138 to Yabe, the disclosure of which is incorporated herein by reference, describes an endoscope having an imaging unit at its distal end, which is designed to be replaceable by a technician for ease of maintenance.
U.S. patent publication 2004/0082883 to Kohno, the disclosure of which is incorporated herein by reference, describes an ultrasound endoscope having a separable head-top to facilitate maintenance.
Instead of using an elongate probe, it has been suggested to use a small video capsule which acquires images within the patient and passes the images to a control station outside the patient. U.S. Pat. No. 5,604,531 to Iddan et al., the disclosure of which is incorporated herein by reference, describes a stand alone video capsule for swallowing by a patient. U.S. Pat. No. 6,632,171 to Iddan et al., the disclosure of which is incorporated herein by reference, describes a clamp for insertion of the capsule into the patient, for example when swallowing is not an option. The stand alone video capsules are limited, however, in collecting biopsy samples and in navigation.
U.S. patent publication 2001/0051766 to Gazdzinski and U.S. Pat. No. 5,653,677 to Okada, the disclosures of both of which are incorporated herein by reference, describe endoscopes having detachable video capsules.
U.S. Pat. No. 6,916,286 to Kazakevich, the disclosure of which is incorporated herein by reference, describes an endoscope having a video unit rotatably mounted on the distal end of the endoscope.
These endoscopes are complex and may be difficult to sterilize.
As sterilization of endoscopes is relatively difficult, disposable sheaths which cover an endoscope are used to isolate the endoscope from the patient tissue, so as to avoid time-consuming cleaning and disinfection processes. In some cases it is desired to have one or more channels run along the endoscope. These channels may be used, for example, to pass tools and fluids (e.g., water, drugs, air) to body tissue and/or to remove fluids from the body (e.g., using suction). As the sheath should completely isolate the endoscope from the human tissue, such channels are generally attached to the sheath, and do not extend within the endoscope. This, however, enlarges the cross-section of the sheath-covered endoscope being inserted into the patient. Such a larger diameter may make the insertion of the endoscope more difficult or may prevent the insertion altogether. In addition, the loading of the endoscope into the sheath is a complex task, especially since it should be done in a sterile environment, or, at a minimum, a contaminant-free environment.
U.S. Pat. No. 5,892,630 to Broome, the disclosure of which is incorporated herein by reference, describes a disposable endoscope, which has a non-disposable optical portion at its proximal end. While this endoscope may solve the problem of sterilization, it may not provide an image of sufficient quality.